Bed plate



Nov. 8, 1932. A. J. ALLISON 1,386,361

BED PLATE Filed Sept. 17, 1928 Patented Nov. 8, 1932 Ares UNITED PATENT oFFlcE ALBERT :r. ALLISON, or narrow, onraassrenon, BY MESNE ASSIGNMENTS,'TO 'srMoNns wonnmv WHITE COMPANY, A CORPORATION OZFYOHIO BED PLATE Application filed September 17, 1928. Serial 1101308360.

This invention relates to beaters for mechanically treating pulp (called stufi) in the manufacture of paper, and it is more particularlyconcerned with improvements in the bed plate of a beater, whereby the output of-the beater is increasedand the quality of the product improved.

The oldest type of beater known, and the one most extensively used to this day, is called 1-0 the'Hollander, and it comprises a large tub,

oblong in plan but having circular ends. A

partition in the middle parallel to the sides, which partition terminates some distance from each end, converts the tub into an endless channel in which the stuff in the tub circulates. This partition is called the midfeather. A massive roll is mounted to rotate in the space between the midfeather and one side of the tub, on an axis normalto the midfeather. Radiating from the roll, parallel to its axis, is a number of blades called fly bars. Directly below the roll is the bed plate, and it is with improvements in the bed plate that my invention is concerned.

The most common form of bed plate consists of a number of flat metal strips or bars, I

standing on edge and bolted together with a thin layer of wood between each two strips, formingnarrow spaces between the strips. 3" When the bed plate is in position its bars lie parallel or substantially parallel with the shaft of the roll. The bed plate is secured in a chair or drawer built in the bottom of the tub, and by means of adjusting mechanism the roll is moved up ordown to bring its fly bars into the desired position with reference to the edges of the bed plate bars. The fly bars act upon the stuff in the tub much as the blades of a boats paddle wheel, and the stuit is thus made to circulate around the midfeather. By this means the stufi' is carried across the bed plate and in transit is beaten between the fiybars and the bars of the bed plate. One function of the beater is to disintegrate the fibrous material used in making paper; another is to cutthe individual fibres to suitable lengths, depending upon the character of the material and the kind of paper to be made therefrom. Other. characteristics, may or may not be imparted to the fibres, as desired, but in all cases two things are important in beating paper stock: (1) the material should be abundantly hydrated, and

2) generation of heat should be avoided. ne of the objects of this invention is to secure these desideratab Another object is to control the flow of stuff around the circuit so as to more thoroughly. mix the components; also to insure uniform treatment of all the stuff. Other objects are toreduce impedance to the flow of stuff, and to reduce the consumption of power.

Without further preface I shall proceed to describe an embodiment of my improved 5 bed plate, assisted by the accompanying drawing, in which i Fig. 1 is a plan View of my improved bed plate; 7

Fig.2 is a side elevational view, and Fig. 3 is a cross section. Fig. 4 is a longitudinal section of a portion of a heater equipped with my bed plate. The,

section is supposed to be taken just back of the near wall of the tub, so only the tub is shown in section, and the figure is to a considerable extent diagrammatic.

- The base of my bed plate consists of a tray or box composed of two members, 10%10, which are drawn together with bolts 11. Standing on edge in this box are the strips or bars 12 of the bed plate. These are broad, thin strips of metal, corrugated. Be tween the bars are spacers 13. The bars and spacers are clamped together by drawing the halves 10-10 of the box together with the bolts 11. The bars 12 are free-standing above the walls and spacers and run diagonally across the bed plate, leaving the spaces between the bars open at each end.

'Fig. 2.

The inner sides and ends of the tray walls lean inward, as at 14, while the ends of the bars 12 and spacers 13 flare outward toward the lower edges of the bars, thereby forming a sort of dove-tail or interlocking arrangement for keeping t-l e bars and spacers from rising in the tray. The portions of the bars which abut the ends of the tray are notched to produce the flare which co-acts with the leanin walls 14;, while allowing the ends of the haes 12 to extend over the end walls of the tray, as at 'l5. The bolts 11 pass through round apertures in the side walls of the members l0. These bolt holes open into grooveslbttormed in the-portions of the members 10 which serve as the bottom oi the tray, the grooves being of such depth that" Fig. 3. Since thebars and spacers are wholly on one side otthe'bolts and there is no counter-action on the other side of the bolts,

screwing down the nuts on the bolts to clamp "the bars andspacers tends to bend the bolts and distort the tray. tendency and relieve the bolts of this bending To counteract this moment Lconnect the two members 10 with a series of transversely disposed splines or guides, in the form of heavy "steel rods 18.

These fit in holes formed inbosses 19 cast on the under side of the members 10. One ofthe'se bosses can be seen in Fig. The bosses are also shown with dotted lines in Referring now to Fig. 1-, my improved bed ,plate is seen in the chair, which in the presnt case is an open iron box 20 secured to the bottom 21 ofthe'tub. The bed plate is fastened in the chair with wooden wedges 22 in the usual way. The roll 23 shown in this figure-hasthe usual fly bars 24 radiatingfrom its periphery. The vertical walls 25 and26 oft-he chair 20 are so proportioned that the fly bars clear the upper edges "of the walls by a substantial distance. This dis- 'tance will vary in practice, according to the "position of the rolljbiit when the bars of the bed plate are new 1 prefer having the fly b'a'rs'cl'ear the 'walls 25 and 26 by about 1 Abutting the wall 25 is a ramp 27, andat the other sideof the-chair there is what is known astheback-'fall, 28. This is a sort of dam "inthe circuit, one side of which conforms approximatelyfto the beater roll, while the other side 'slops down to the bottom of the tub. The curved side of the back-fall ter1ninates at the top of the wall 26. It will be noticed that the side Walls of the bed plate ba-se the members 10-10, are about the heightof the walls 25. and 26 of the chair 20. Therefore the Stuff circulating in the tub has free access to the open spaces between the bed plate bars and the stud can flow through these spaces or channels'troni one side to the other of the bed plate.

The width of the inter-bar spaces or channels is much greater than the thickness of the bars, making the channels very commodious, the reason for which will be explained presently. Corrugating the bars stiffens them and enables the bars to be made thinner than free-standing bars otherwise could be made. In practice I prefer to make the bars about thick, although they may be made thinner, and I have them extend above the spacers 13 about 1 or 2". These dimensions are merely suggestive, h wever, and I dofnot limit myself thereto. 'Fu'r'thermore, in practice the bars are gradually reduced in height by wear, and finally it becomes necessary to renew the bars. The diagonalof the bars alsoghas the effect of stiffening them, independently of their being corirrigated, and it helps to prevent their vibrating. 7 V

As'I have previously said, the fly bars'act upon the still? much as would the blades of a boats paddle wheel, and the stuff is thereby made to circulate around the midfeather.

This circulation is accelerated by the backfall. The roll carriesthe stuff up to'and over the crest of -theback-fall and the 'stuti' is given momentum by its descent of the slope.

Theclearance between' th'e fly bars and the back-fall is usually in the neighborhood of The rotation o'f the rol l produces-a powerful suction in this space and it is this, to a considerable extent, which carries the stu'ii" up to'the crest of the back-fall. Where the bed plate isof the usual form, consistin g of bars running parallel or si'ibstairtiallily parallel to the roll shaft, the bed plate ob st'r'u'c'ts the passage and limits the flow of stuff practically 'to "that which is *cafiried across the bed plate in the spaces between the fly bars, together with what passes at each end of the roll and bed plate. Thus in the -'o ld arrangement the suction created by the roll i's'cou nte'r'a'c'ted to aconsiderable extent and consumes power by tending to retard the roll. In the use of my present bed plate less power is consumed. As the stall can *flow freely through the commodious inter-bar "channels, these channels being" open at each end, there notonly is little or no counteraction, em the suction contributes to the flow o f'thestufi? through the inter-bar "channels-in the bed -plate.- Thus by the use of my improved bed plate'the circulation of the stuff is very much and the desired re-hydration.

fibrage should thenbe changed and re-hydrated, or new fibrage picked up on the fly bars before the bars en a e the next bar of the bed plate. lVith the old style bed plate too little of this occurs. There is nothing to bring about this; renewal of the fibrage bundles, The stuff trapped between the fly bars as they start to traverse the old style bed plate is substan tially stagnant and there is but little to produce the desired readjustment and re-hydration of the fibrage. The stuff flowing along the inter-bar channels of my improved bed plate is agitated by the corrugations, and the resulting turbulence serves to deposit new fibrage on the edges of the fly bars and bed plate bars, resulting ina substantially uniform action on the stuff by all of the bed plate bars.

The diagonality of the bars contributes to this eflect to a certain extent independently of their corrugations, because the flow of stufl along the inter-bar spaces is in a different direction from the movement of the fly bars of the roll. Another advantage of the diagonality of the bars of the bed plate lies in the fact that the total area of contact between the bed plate and fly bars is always substantially the same, and this total is made up of a large number of small isolated areas of contact. Because of this very little heat is generated, compared with the heat generated by the co-action of fly bars with the transversely lying bars'o-f the old style plate. Furthermore, the constant flow of a comparatively large volume of cool stuff on each side of the free standing, comparatively thin bar carries off the heat which is generated. The

result is that the roll can be revolved at a higher velocity than usual, and if desired it can be run in closer relationship with'the bed plate bars, all without danger of burning the stuff. Obviously the fibrage is abundantly hydrated during all of this action.

Because of the diagonality of the bars in my improved bed plate stuff flowing through its inter-bar channels is diverted to some extent toward one side of tub circuit. This can be utilized in overcoming a problem which has long puzzled designers of beaters. It has been found that certain regions of stuii are stagnant, i. e., there is not much movement of the stuff in those regions. By leaning the bars in the desired direction this stagnant stuff can be driven into the current.

As is seen in Figs. 3 and 1, the upper face of my bed plate has the curvature of the roll. That is, the upper edge of each bar is hollowed so each fly bar in the roll can touch it from the time the fly bar enters the zone in which the bed plate lies until it leaves the Zone. Taking the diagonality oi the bar into account and considering the roll as a cylinder, it is plain that the edge of the bar must be adapted to fit the surface of a cylinder when the longitudinal axis of the barforms a given acute angle with the axis of the cylinder.

The angularity of the bars in my bed plate with reference to'the axis of the roll may be of various degrees, within reasonable limits:

on one hand the angle must be large'enough to carry the bar across the bed plate, so. stuff can floW through the inter-bar channels from one side to the other of the bed plate, but, on the other hand, if the angle be very large, so

the bars lie too nearly parallel with the. midfeati.er,.their effectiveness will be impaired. Furthermore, it is possible with my improved bed plate to make the flow through the interbar channels too free for some kinds of stock.

One way of preventing this is to reduce the width of the spacers 13. Anotheris to reduce the depth of the inter-bar channels. In apaper mill having a large number of heaters this can be managed by putting-stock into a beater the depth of whose inter bar As I have already intimated, some of thebenefit of my invention would be obtained with straight bars, although corrugated bars are much more effective. The pitch of the corrugations should be so proportioned to the length of the bars that there will be an even number of corrugations, in the 'bar-., Thus each end of the bar is enabled tom'eet the side wall of the adjacent member 10-nearly perpendicularly, allowing; the 'bars to interlock with the walls of the tray, as in Fig. 3. i

While I have here shown only one embodiment of my invention, I have shown in my application Serial No. 258,500, filed January 21, 1928, two other structures, each of which could be adapted to use as a bed plate. Nor is it to be-understood that myinvention is limited in its application to these embodiments. The scope ofmy invention is indi-:

cated by the appended claims, to-wit:

1. A bed plate comprising a box consisting of two parts, bolts for drawing said parts together, bars standing on edge in said box,

spacers separating the bars, said bars and spacers being secured in'the box. by drawing the two parts of the box together to clamp the same therein, the bars being further secured by interlocking with the wallsof the box.

2. A bed plate comprising a box consisting of two parts, bars standing on edge in and extending diagonally across the box, the bars extending a substantialdistance above the walls of the box, said walls having inwardly leaning surfaces and the contiguous ends of the bars flaring outward toward their lower edges, thereby forming a dove-tail interlock,

spacers between the bars, which spacers are no higher than the walls of the box, thereby leaving the bars free standing above the walls" of the box, and means for drawing the two parts of the box together to clamp the bars and-spacers together. I

3. A bed plate comprising a box conslstlng of two vpart s, bars standing on edge in and extending diagonally across said box, the bars extending a substantial distance above the walls of the box, said walls having inwardlly leaning surfacesand the ends of the bars flaring outward toward their lower edges, thereby forming a dove-tail interlock, spacers between the bars, which spacers are no higher than the walls of the box, thereby leaving the bars free standing above the walls of the box,

means fo-r drawing the two parts of the be together to clamp the bars and spacers together, and splines for guiding the parts of I the .boX, to prevent distortion of the ensemble.

4. As'an article of manufacture, a bed pla'te -bar comprising aflat strip of metal of uniform thickness, said strip being at least seven times as wide as it is thick, and each end thereof from a point about midway its edges to one edge being cut obliquely to form an acute angle with one and the same edge.

5 As an article of manufacture, a bed plate 7 bar comprising a strip of metal of uniform thickness, corrugated transversely, one edge sai'djbar being hollowed to fit thesurface of a cylinder when thebar abuts said surface edgewise and the longitudinal axis of the bar forms an angle of at least twenty degrees with the axis of the cylinder.

'6. As an article of manufacture, a bed plate bar comprising a strip of metal of uniform thickness, corrugated transversely from one long edge of the bar to the other, the corrugations being so proportioned that there is an even number-of corrugations, making one end=o f the barcurve toward one side and the gthe-r end toward the opposite side of the 7 As anarticle of manufacture, a bed plate bar comprising a corrugated strip of metal of uniform thickness, the corrugations running from one long edge of the bar to the other, and so proportioned that there is an even number of corrugations, making one end of the bar bend toward one side and the other end bend toward the opposite side of the bar, each end of the bar, from a point about midway its edges to one edge, being cut obliquely to form an acute angle with one and the same edge.

8. A bed plate comprising a base, freestanding bars mounted therein, running diagonally across the plate, the spaces between the bars being much wider and deeper than the thickness of the bars and open at each end to permit free flow of stuff there- Ithrough, the bars being firmly secured in the base .so they'can neither rattle nor rise therefrom, the bars being corrugated perpendiculady to thebase. 

